"The US and hostile forces jumped to conclusions that the republic is planning the third nuclear test, citing their hypothesis and argument," said the propaganda weekly, Tongil Sinbo.

North Korean leader Kim Jong-un had vowed to take "substantial and high-profile important state measures" over the ongoing speculation about a nuclear test in the country. The remarks were widely seen as a direct reference to an imminent nuclear test, although Kim did not say so explicitly.

The latest report in the weekly, however, warns that the US and other countries do not know what Pyongyang means by important measures - whether it is the much-feared nuclear test or something even worse.

The mouthpiece says that the measures "are aimed at safeguarding its national interest and not at threatening anyone", adding: "It remains to be seen what the important state measures are, though it is clear that any US reactions to them may prove to be only irrevocable losses."

Only a week ago, Pyongyang was forced to remove a promotional video that reportedly showed a city attacked by North Korean missiles. The city was indirectly referred to as New York.

"Black smoke was billowing somewhere in America. Maybe the group of Satan, who has been habitually conducting an invasion war, are burning in the fire they set themselves," said a background message in the video.

If the nuclear test goes ahead, it will be North Korea's first under the leadership of Kim Jong-un. The test will also signal the world that the new leader continues to follow the path of his father Kim Jong-il and grandfather Kim Il-sung, both of whom strengthened the country's military programmes despite international condemnation.

Experts earlier predicted that Pyongyang may conduct a test to mark Kim Jong-Il's birthday in mid-February, when the newly elected Park Geun-hye will also be sworn in as South Korean president. North Korea's last known nuclear tests were in 2006 and 2009.